The rebels launched the coup in response to Diem's autocratic rule and the negative political influence of his brother Ngo Dinh Nhu and his sister-in-law Madame Ngo Dinh Nhu. They also bemoaned the politicisation of the military, whereby regime loyalists who were members of the Ngo family's covert Can Lao Party were readily promoted ahead of more competent officers who were not insiders. Dong was supported in the conspiracy by his brother-in-law Lieutenant Colonel Nguyen Trieu Hong, whose uncle was a prominent official in a minor opposition party. The main link in the coup was Dong's commanding officer Thi, whom he persuaded to join the plot.